Fixed the underlying problem for the tree not being colored correctly
after loading proofs (treeSelectionListeners were previously stored in
BoardStates, and were not being notified of changes after a proof was
loaded due to being different objects than the ones referenced/stored in
boardstates). This also fixed an issue with manual case rule
construction in proofs after loading. In the process of fixing this, a
resource leak was found: when a puzzlemodule was loaded, the old one was
still referenced as a tree selection listener/transition change
listener. Fixing this likely fixed the issue with treetent's links being
read as lightup data, causing exceptions.